#ifndef _CONSTANT_H_
#define _CONSTANT_H_

#define MATH_PI 3.1416
#define RADIUS  2
#define CIRCLE_AREA  (MATH_PI * RADIUS * RADIUS)  // MATH_PI和RADIUS必须在此之前已经定义

typedef enum {
	BLACK,
	RED,
	GREEN,
	BLUE,
} COLOR;
extern COLOR my_color;
void set_color(COLOR new_color);
COLOR get_color();

#endif
